Thorn Cycles Forum
Community => Thorn General => Topic started by: mickeg on March 28, 2017, 10:02:42 pm
-
When did Thorn start putting disc brake fittings on their forks?
https://www.sjscycles.co.uk/forks/48-26-650b-thorn-nomad-disc-fork-yellow-gloss/?geoc=US
I was unaware that they started to use disc brakes up front. I have no plans to change to disc, but I know that some have strong pro-disc opinions.
Is this new or did it happen a long time ago and I did not notice it?
-
It was released July 2016. Note that this fork is only for 650B wheels, not 26-inch wheels. 650B wheels are about 27.5" (https://en.wikipedia.org/wiki/27.5_Mountain_bike (https://en.wikipedia.org/wiki/27.5_Mountain_bike)).
These forks are only for disc brakes, not rim brakes. Apparently (see below) there are no 650B rims available for rim brakes. These forks do not have mounts for rim brakes.
See page 35 of the latest Thorn Mega brochure
http://www.sjscycles.com/thornpdf/THORN_MEGA_BROCHURE.pdf (http://www.sjscycles.com/thornpdf/THORN_MEGA_BROCHURE.pdf)
Here is the text from page 35 of that brochure:
------------------------------------------------
At the end of July 2016, we will have disc forks which will fit our NOMAD frames. We will then be able to offer both 26" and 650B options on the Nomad. The 650B option will only be possible with front and rear disc. I’m convinced that 26" wheels will remain the sensible option for expedition cycling indefinitely. 650B has proved popular on MTB’s because 29er bikes with suspension are too big for many riders. Tyre manufacturers are not introducing 650B tubeless tyres for quick road use*. There are a few tyres which could prove excellent for a 650B Euro-Style disc brake touring bike which is what I shall be offering.I shall be offering Schwalbe Almotion Tubeless Tyres 2.00" which are fairly heavy at 750g and I would be amazed if they came anywhere close to being as good in any situation as the legendary 26" DUREME.
The Schwalbe G-ONE is a superb, tubeless gravel bike tyre and it’s available in 650B 1.5" 420g. Perhaps this will prove to be the most popular option on a disc braked Nomad?
I haven’t settled on rims yet.
I expect that the Schwalbe Marathon Supreme HS469 tubed tyres, which are available in 650B 1.6" (470g) and 2.00" 600g will be the most popular on the Euro NOMAD.
Rim manufacturers are not making rim brake rims for 650B*.
*There’s a small movement in the USA which does have access to quick 650B road tyres and lightweight rim brake rims at very high prices but these are for the long distance Audax market and I believe that all but the shortest of these cyclists would be better served with wide tubeless 700c tyres such as the 30c Schwalbe S-One.
Andy Blance 1/May/2016
------------------------------------------------
- DaveS
-
It's a bit of a UK turn for Thorn but I suppose they have to move with the times. Quote from a previous brochure.
Please don’t ask for a disc brake on
steel forks, we simply won’t do it!
We use raked blades, these are exceptionally comfortable, they will
withstand the forces of cycling (and have done so for generations) but
raked forks will not withstand the forces generated by a disc brake,
which are very different to the forces generated by V brakes, even at
the same rate of retardation. We have seen 3 ways that other
manufacturers have “accomplished” this, they all seem stupid to us
(1) We have had customers complain that a well known custom
builder’s raked steel forks have permanently bent under braking.
(2) We have seen hideously uncomfortable, thick walled, straight
blades used by another manufacturer, these forks don’t fail, but I
expect that an owner’s hands and elbows soon would!
(3) The most ridiculous “solution” of all, is a heavy left blade and
lighter right blade. The different blades must have different elastic
properties (isn’t that supposed to be the point?) and therefore the
axle must twist, when a bump is hit. If the axle twists, then so must
the front wheel. If the front wheel twists, then the bike consequently
alters course.
Isn’t hitting bumps comfortably and safely the main function of
a bicycle’s fork? Why compromise comfort and safety, in order
to fit a brake, which is inferior, in the conditions that the steel fork
will be used in?
-
I think they haven't changed their mind on heavy-touring bikes. It seems they are providing more options for Euro-style (light weight?) touring.
It is interesting that by making the disc-brake fork only for 650B wheels, they are preventing people from using it for a heavy-touring bike (assuming that a heavy-touring bike will use 26" wheels). Edit: I think I am wrong here. See my comment below.
- DaveS
-
They do one for the Nomad.
https://www.sjscycles.co.uk/forks/48-26-650b-thorn-nomad-disc-fork-yellow-gloss/
-
After a bit of thought, it occurred to me that there is no reason why someone couldn't put a 26" wheel on this fork and use it for heavy-touring with a disc brake. Or am I missing something?
- DaveS
-
I think the fork takes a 26" wheel.
-
Quote from Thorn Mega brochure
"Rim manufacturers are not making rim brake rims for 650B*"
I managed to find some in France, probably NOS. They are fairly narrow, but will take a 50 mm width tyre. I suppose I ought to get a couple of spares, as I still have two bikes with this wheel size, my old utility bike and my wife's main bike.
-
Ok, I missed it last summer when they started making a disc capable fork. Maybe that happened when I was in Iceland, any new news that came out for that month I missed.
My 650b bike that I could not buy a tire for about 30 years ago has been in storage since. In USA, 650b tires were pretty much extinct several decades ago and I could not buy a tire for it. That bike had drum brakes (Sturmey Archer three speed with drum in back). Although I still own the bike, I have several others (including one frame that arrived yesterday) so I have not had a strong interest to get that old three speed operable.
Here in USA, several manufacturers are trying to sell what they say is a new tire size 27.5 and I think some of the dealers never heard of 650b and do not even realize it is an older tire size.
If someone is looking for a 650b rim that works with rim brakes and can't find one, there is a small company in USA called Velo Orange that sells such a rim. But shipping and fees to Europe might be cost prohibitive. But if you are really interested, here is the rim.
http://store.velo-orange.com/index.php/vo-diagonale-650b-rims.html
But I suspect that there are other such rims out there, they just might be hard to find.
-
Just remember that these new Thorn Nomad disc brake forks are only for disc brakes. They have no mounts for rim brakes.
- DaveS
-
Yes, it would have been good if there was canti mounts also for versatility.
-
650B rims for rim brakes are apparently still available here in France :
http://www.xxcycle.com/rim-ambrosio-keba-650b-silver-confreriale,,en.php
Same model as I got, quoted tyre size 28 to 62 mm, IMO best with about 35 mm but works OK with 50mm.
-
Is this fork usable on the Nomad MK2? The website separately lists the (non-disc) Nomad MK2 fork with a MK2 designation.
-
Is this fork usable on the Nomad MK2? The website separately lists the (non-disc) Nomad MK2 fork with a MK2 designation.
I believe it is.
cheers,
Paul.
-
Yes it is, the clue is that the mk2 Nomad came in yellow.
-
Is this fork usable on the Nomad MK2? The website separately lists the (non-disc) Nomad MK2 fork with a MK2 designation.
Thank you. Now I know that I was not the last person to learn that they now make a disc comparable fork.
-
650B rims for rim brakes are apparently still available here in France :
http://www.xxcycle.com/rim-ambrosio-keba-650b-silver-confreriale,,en.php
Same model as I got, quoted tyre size 28 to 62 mm, IMO best with about 35 mm but works OK with 50mm.
Thank you for saying "quoted tyre size" instead of repeating the range as fact. From its ETRTO sizing, that suggests an inner width about 19mm.
I never trust rim manufacturers anymore when they cite a tire width for their rims. A few examples below:
- Ryde Andra 30 - Inner width 19mm - Recommended tyre widths: 28 to 62 mm
https://www.sjscycles.co.uk/rims-tape/rigida-andra-30-26-559-mtb-rim-rohloff-drilling-black-32-hole/?geoc=US
- Mavic A719 - ETRTO suggests inner width is about 19mm but I measured mine at 20mm - Recommended tyre widths: 28 to 47 mm
https://shop.mavic.com/en-be/a-719-j24400.html#1028=3283&1035=3501
I used this rim on my Long Haul Trucker with 37mm tires, now use it on my rando bike with 32mm tires.
- Velocity Dyad - Inner width 18.6mm - Optimal Tire Width: 25mm - 38mm
http://www.velocityusa.com/product/rims/dyad-622
These are going on my new build, initially with 37mm tires.
When all these tires with the 18 to 20 mm inner widths have such varying recommended tire sizes, I think that the marketing departments at those tire companies are in charge of writing specifications. I can say that my Andra 30 rims are clearly too narrow for a 57mm tire, which is the tire that I usually ride on my Nomad with those rims. Yet at 57mm, it should work great because Ryde says the rim is good for up to 62 mm.
I prefer the chart near the bottom of this page for determining which tires fit which rims.
http://www.sheldonbrown.com/tire-sizing.html
When I built up my Sherpa, I planned to use tires in the 37 to 50 mm range. Thus, from that chart I went shopping for a tire that had an inner width of about 21 or 22 mm. I bought the Salsa Gordo (now discontinued) and I measured that rim at 21 mm. Great rim, I wish I could still buy them.
http://salsacycles.com/components/archive/category/rims/gordo_26
-
Thank you. Now I know that I was not the last person to learn that they now make a disc comparable fork.
Always happy to be of help ;D
-
- Ryde Andra 30 - Inner width 19mm - Recommended tyre widths: 28 to 62 mm
https://www.sjscycles.co.uk/rims-tape/rigida-andra-30-26-559-mtb-rim-rohloff-drilling-black-32-hole
I can say that my Andra 30 rims are clearly too narrow for a 57mm tire, which is the tire that I usually ride on my Nomad with those rims. Yet at 57mm, it should work great because Ryde says the rim is good for up to 62 mm.
The Andra 30 rims work OK for me with 50mm tyres, but I reckon wider rims would be better for this size of tyre (Andra 40 or similar). But my Andra 30 rims are CSS, so they should last a very long time before I need to replace them.
-
- Ryde Andra 30 - Inner width 19mm - Recommended tyre widths: 28 to 62 mm
https://www.sjscycles.co.uk/rims-tape/rigida-andra-30-26-559-mtb-rim-rohloff-drilling-black-32-hole
I can say that my Andra 30 rims are clearly too narrow for a 57mm tire, which is the tire that I usually ride on my Nomad with those rims. Yet at 57mm, it should work great because Ryde says the rim is good for up to 62 mm.
The Andra 30 rims work OK for me with 50mm tyres, but I reckon wider rims would be better for this size of tyre (Andra 40 or similar). But my Andra 30 rims are CSS, so they should last a very long time before I need to replace them.
At high pressures the 57mm tires work pretty good on Andra 30 rims, but not at lower pressures. I had to run much higher pressures in my 57mm Marathon Extreme tires on some very rough roads in Iceland last summer than I wanted to run them at. After that I started giving serious consideration to replacing my CSS Andra 30 rims too. But I agree with you, my rims will likely last forever. And Andra 40 CSS rims are not sold in USA, so I would be looking at very expensive shipping to get a pair of very expensive rims shipped from Europe.
http://www.ryde.nl/andra-40
Other brand rims are not drilled for Rohloff and are not CSS, so I am less enthusiastic about other rims. And when I have to pay retail prices for spokes, building up a wheel with different brand and model rims would push the costs even higher. But if I stayed with Andra series of rims, I think the ERD is close enough that I could re-use my spokes where other rims would likely require a different spoke length. I build my own wheels, so there is no cost of labor.
When I built up my Nomad, I unfortunately believed the Thorn brochure that said it was a great expedition rim, the photos of the yellow Nomad in that same brochure with Marathon Extreme 57mm tires made me believe that the tire and rim combination would be a good one. So, instead of researching rims the way I previously did for my Sherpa where I started with my planned tire sizes and then looked for a rim that would work best, I just ordered the Andra 30 rims based on their recommendation.
-
I'm pretty tempted by these 650B wheels. I wonder what it would do to handling if I had 26" in back, and the 650 up front?
-
I wonder what it would do to handling if I had 26" in back, and the 650 up front?
Well...probably nothing if you used a 26x2.0 Dureme up front and a 650x38 Compass/Grand Bois Lierre in the rear -- the outside diameter is essentially the same.
For a more complete discussion of how changes in tire size -- or mixing sizes -- and fork offset/rake can affect handling and effective trail, see my article here:
http://thorncyclesforum.co.uk/index.php?topic=4245.msg19567#msg19567
I have another article on the subject here:
http://thorncyclesforum.co.uk/index.php?topic=3893.msg20016#msg20016
A check on the canti post placement and available brake adjustment on my former Sherpa and current Nomad showed I could run 650B rims if I wished.
Best,
Dan.
-
Yes it is, the clue is that the mk2 Nomad came in yellow.
I just had my shop fit the fork to my Nomad Mk2, and discovered a couple issues:
- The fender fittings have moved several inches, which means I'll need new stays
- The rack and fender fittings are now M5, rather than the beefier M6 of the original fork. I have no idea if using M5 bolts though M6 sized holes on the rack is an issue. Danneaux?
The rack mounts need the threads chased anyway, so I'll just ask my LBS to solve the issues.
---
edited to fix typo in Danneaux's name
-
Hi George!
The fender fittings have moved several inches, which means I'll need new stays
Simplest and cheapest option here for 'Merkins is a fresh set from Planet Bike. If you get their stays, do yourself a favor and also get their nice stay caps (unless you plan to trim the stays flush) and a full set of their really nice polished stainless drawbolts and 10mm nylock nuts. The lot is available with free shipping in CONUS and is available from this link: http://ecom1.planetbike.com/smallparts.html
The rack and fender fittings are now M5, rather than the beefier M6 of the original fork. I have no idea if using M5 bolts though M6 sized holes on the rack is an issue. Danneaux?
The quick answer: You should have no trouble. Just be sure the rack is pushed down against the bolt shanks (threaded part of the machine screw) before tightening and use thread locking compound.
TLDR: Long, involved answer...
While it is ideal to have the rack hole match the bolt shank's OD to within about 0.1mm oversized, in practice there is little problem. Rack mounting bolts are more likely to break if they are overextended (i.e. if a mudguard stay eye is attached between the rack mount and the dropout) or if the bolts get loose and the rack can fret (work back and forth) or pound outright on the bolt threads. In most cases, it pays to keep the bolt threads on the rack side of the dropout as short as possible. On front racks and eyelets, I will often run my bolts from the inside out, so the head is trapped inside, then use a nylock nut to secure the rack on the outside. This allows the bolt to be removed easily in case it breaks. Andy Blance does the same. I frequently do this also at my seatstay mounts. It is rarely possible to mount a rack this way on the right dropout because of limited clearance between the chain and dropout that would foul the bolt head.
Nearly every rack on the market (I have personally checked almost 30 now) have holes drilled sufficiently large to accept 6mm bolts. Certainly Tubus, Surly, and Thorn racks will accept 5mm or 6mm. My 2011 Thorn Sherpa Mk2 came with frame rack mounting bosses threaded at M5x0.8 and worked fine with Thorn Low-Loader Mk V front and Surly Nice Rack rear racks drilled to accept M6x1.0 bolts.
Ideally, the larger bolts are both stronger and more secure -- they are 16.7% larger in outside diameter. I can feel the difference 6mm fittings make and the difference in stability was measurable in my testing; the more robust mounts resulted in less lateral sway, but I think the core reason is not just the bolt thread side but the larger OD of the mounting boss which offered better bracing.
When I braze my own racks from cromoly tubing, I mill the bottom stanchions from steel billet and use stepped fittings: The through-hole clears the bolt threads with 0.1mm clearance and the allen socket head is recessed into the stanchion on a slight countersink with 0.1mm head clearance. I turn the underside of the bolt heads to match the slight taper of the shallow countersink. It makes for a nice, flush fitting and since the stanchion well is conical, the rack mount self-centers over the bolt head and threads. I also employ solid billet inserts between the rack tubing and stanchion so the joint is effectively lugged internally and has a larger wetted area when I braze it. Makes for a very strong connection. The rear rack I built for my Folder has no problem holding my 78 kg when I stand on when it is mounted to the bike. Photo of its mounting stanchion and recessed bolt below.
All the best,
Dan.
-
Agree with Dan, M5 bolts are ok when the rack is drilled for M6 bolts. I also have several racks that will take M6 bolts, but I use M5 on all bikes except my Nomad which uses M6. And since you are talking about the fork, that is the front where you likely are not loading it down with 20 kg of weight on each side, making M5 more likely to survive quite well.
Dan mentioned the stay caps, so I thought I would point out another option. I recently built up a Titanium touring bike (oops, not Thorn, sorry) and within a very short distance of riding the toe overlap meant that I had already knocked the stay cap off of one of my stays. The only color on the entire bike was two taillight lenses (red) and a headbadge (also red), but everything else was bare metal, black or white. So, I decided to add a bit of color, instead of black fender stay caps I got red caps for all of my fender stays. Looked neat enough that I pulled the black ones off of my Nomad and put red on there too. Both bikes have black fenders. I like to keep my fender stays long enough that if I put them on a different bike, I have minimal risk that the stays will have been cut too short, thus I always have about 10 to 20 mm of stay sticking out past the fender bracket. Shipped from Asia, expect it to take several weeks. Package of 100, so I can keep losing them and have plenty of spares.
https://www.amazon.com/gp/product/B01N9VWPMJ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
In the event that the above link does not work, or in the event that you try to order from a different country version of Amazon, I pasted some of the description here:
uxcell 3mm Inner Dia Rubber Hose End Cap Screw Thread Protector Cover Red 100pcs
Ships from and sold by uxcell.
Product Name: Thread Protector Cover; Country of Manufacture: CHINA
Material: Rubber; Net Weight: 26g
Package Content: 100(+/-2%) x Thread Protector Cover; Main Color: Red
Total Size: 16 x 5mm/0.63'' x 0.2''(L*D)
Inner Dia.: 3mm/0.12''
Photo, you can only see a couple stays in the back of the back fender on the bike closest to the camera. Ok, with panniers, there is some color, but without any touring gear on the bike it is nearly colorless.
-
Very nice, George (mickeg)! :)
Vinyl vacuum caps from the automotive store will also work (I had red ones on my red tandem for awhile but have since switched to different mudguards/fenders that have a black plastic cap joining two co-located stays.
All the best,
Dan.
-
Thanks to you both! Very thorough, and I shall cease my fretting on this topic.
-
Just FYI -- I have my Nomad back and it is a thing of beauty. Back to a rigid fork, with fenders and racks all fitted, and disc brakes, so it will stop even in pouring rain ;D
-
Yay! So glad the results are proving satisfactory for you, George.
How is the ride quality? Have you noticed any difference in front end stiffness/shock absorption from the more rigid disc fork?
Any photos available? Photos are always good, especially those showing mudguard/fender struts with disc mounts. ;) :D
Also, what disc calipers did you go for? TRP Spyke/Spyre for added rear rack clearance?
All the best,
Dan.
-
Dan, this is the setup we discussed back in http://thorncyclesforum.co.uk/index.php?topic=8871.0, where I eventually went for the Hope hydraulic brakes with a suspension fork. As Dave Whittle pointed out, these are low-enough profile to work.
Attached are pics with the new rigid fork, and disc brakes, along with a pic of the rear brake.
-
How do I rotate images, so people don't have to turn their heads sideways?
-----
Ooh, 100th post -- finally a full member after only 5 1/2 years. Perhaps I should be more loquacious.
-
Thanks so much for the photo updates, George. I am sure a lot of people will appreciate the photos. Sometimes, people contact me asking questions they are shy about asking themselves online, so these will answer some queries.
I have one more...
George, did you abandon drop handlebars/levers when you switched to the Hope hydraulics? Or do you use a slave actuator/remote reservoir with cable actuation? As I recall (perhaps incorrectly), your Nomad started with drops.
Thanks!
All the best,
Dan.
-
How do I rotate images, so people don't have to turn their heads sideways?
I selected the photos en masse on one of my Windows PCs (7 Ultimate in this case) and rotated, then saved them. I then reduced the images for faster loading and to fit the screen using Image Resizer for Windows. I then selected them individually and uploaded below.
Sadly, there is an anomaly in the Small Machines Forum software that doesn't readily allow substitution of photos once the maximum of 4 per post have been uploaded. Otherwise, you could simply have edited your post to upload the rotated images (or I could have done so for you). When posting, you can substitute other photos, but once the cake has been baked, you're out of luck. Once four images have been uploaded, the only option is to deselect them.
As for taking five years to make 100 posts/Full Membership, "Wise men speak because they have something to say..." -- Plato.
;D Congratulations on your "century of posts"; it has been nice having you aboard, George.
All the best,
Dan.
-
For future reference, I could look at the bigger photos on my screen by pressing control/minus <the minus key> several times.
-
For future reference, I could look at the bigger photos on my screen by pressing control/minus <the minus key> several times.
Yep! A handy and worthwhile reminder, George. :)
Also depends on the browser and also on whether a mobile platform (i.e. tablet, smartphone) is used.
We used to have a posting limit for attachments, set by the software. That has changed in the latest software version but file sizes generally something below about 500MB/photo seems to work pretty well.
All the best,
Dan.
-
...
We used to have a posting limit for attachments, set by the software. That has changed in the latest software version but file sizes generally something below about 500MB/photo seems to work pretty well.
All the best,
Dan.
Do you mean 500 kb? 500 meg is pretty big, bigger than any camera I can afford.
For posting photos, I usually photo reduce photos down to 20 percent of original size, then usually less than 500 kb.
-
Do you mean 500 kb? 500 meg is pretty big, bigger than any camera I can afford.
;D ;D ;D ! For posting photos, I usually photo reduce photos down to 20 percent of original size, then usually less than 500 kb.
Yes! Good job, George.
All the best,
Dan.
-
George, did you abandon drop handlebars/levers when you switched to the Hope hydraulics? Or do you use a slave actuator/remote reservoir with cable actuation? As I recall (perhaps incorrectly), your Nomad started with drops.
The Nomad has always been straight bars. I bought it strictly for off-road use, and my usual Nitto Noodles didn't seem like the answer.
-
The Nomad has always been straight bars. I bought it strictly for off-road use, and my usual Nitto Noodles didn't seem like the answer.
Thanks, George!
Best,
Dan.